What courses would you recommend to an absolute beginner?

Maybe it would be more useful to have a section (based on Tjalling's courses) such as "chess basics" on lichess where the user can interact, more or less like studies but with a dedicated section.

That would be great specially for newcomers.

One of the plans for the future is to have more organised instructional material like that @Saturn_V
At the very least a section where studies are bundles together, such as Tjalling's Pre-Course in draughts
Ideally a dedicated section with basic concepts of tactics / strategy / endgames / etc and exercises, close to what lichess offers

standard draft puzzles increase their difficulty level very quickly, they could make the puzzle level increase more gradually.

It depends on your puzzle rating. The higher it gets, the more difficult puzzles you get. So if you solve many early on, they will become more difficult quicker. But that should average out to your real level on the long run.

You can't post in the forums yet. Play some games!